Relay coil construction



I. L. MITCHELL RELAY COIL CONSTRUCTION June 10, 1958 2 Sheets-Sheet 1 Filed June 27, 1956 INVENTOR. Irv/79L. MHche/l 2 Sheets-Sheet 2 Filed June 27, 1956 IN V EN TOR. I/W/IJL. MH'c/ve/ BY guy/wk Avfonney.

United States Patent RELAY COIL CONSTRUCTION Irving L. Mitchell, Rockvilie Centre, N. Y., assiguor to Ebert Electronics Corporation, Queens Village, N. Y., a corporation of New York Application June 27, 1956, Serial No. 594,228

13 Claims. (Cl. 317-458) The present invention relates generally to relay coil construction, and more particularly to a coil construction having two sets of terminals, one to supply current to the coil, and the other independent of the coil circuit and intended for connection to a load line in series with relay contacts, the construction being particularly compact, economical of fabrication, rigid, durable and free of maintenance difliculties.

The invention concerns itself with bobbin wound coils, of the multiplie layer type, such as are wound in large quantities industrially by means of winding machines. It has been the practice in winding coils of the character described to wind the turns of the coil in a series of successive layers, thereafter to apply terminals to the coil, to solder the terminals to the coil ends, and to insulatedly bind the terminals against the mail so that they will remain immovable and rigid during normal use, and while connections are being made thereto. In order to provide effective insulation between the coil and the terminals, it is usual to provide an insulating sleeve between the windings and the terminals.

In accordance with the present invention, the coil itself is wound on a bobbin, and it is desirable to eliminate the insulating sleeve referred to in the preceding paragraph, in order to reduce cost of fabrication, although this is essentially a matter of choice. The coil terminals have leg lengths slightly less than the axial length of the coil, which are laid in spaced apart relation on the coil, extending in a direction parallel to the axis. The terminal ends or feet are bent to extend about one lip of the bobbin, and are provided with the customary threaded openings for receiving small screws, which'enable securing lead ends to the terminals. The load line terminals are generally similar to the coil terminals, and include elongated flat legs and bent feet. The fiat legs are each provided with a vinyl insulating sleeve, and are laid over the legs of the coil terminals, extending in opposite directions thereto. The feet of the load line terminals are bent, as are the coil terminals, to pass over the remaining lip of the bobbin; and are similarly provided with threaded apertures.

After the four terminals have been placed they are to the terminal immediately adjacent. The fact that the terminal feet bend around the lips of the coil bobbin, the legs having such a bend underlying on edge of a lip, prevents axial motion of the terminals in either direction.

In accordance with a further and preferred embodiment of the present invention, one coil terminal and one load line terminal are secured to a strip of insulating material having a length greater than the axial length of the coil. The terminals extend in opposite directions and have ends which substantially overlie the ends of the insulating strip. The coil form or bobbin is provided with end flanges, the lips of which extend outside the coil proper, and are provided with two pairs of aligned circumferential slots, of width slightly less than the width of the insulating strips. The latter are provided with two pairs of opposed slots, in the edges thereof, which interlock with the slots in the lips of the secured rigidly, firmly and immovably to the coil form by the use of suitable electrical tape, wound about the coil and the terminals.

The superposition of the coil and load line represents an important feature of the invention in that it reduces the portion of the coil perimeter which is devoted to terminals, and positions all the terminals in readily acc'essible positions, while separating the coil and load line connections by a distance greater than the axial length of the coil. This feature reduces the probability of faulty installation, or of inadvertent electrical contact between circuits which must remain isolated.

Moreover, the superposition of the legs of the tenninals serves to provide a more rigid, durable and immovable terminal structure than would otherwise be the case, each terminal imparting its strength and rigidity flanges. When the insulating strips have been located in interlocked relation with the slots in the lips of the flanges, they are bound to the coil by suitable tape to prevent radial motion of the terminals with respect to the coil, i. e. to prevent loss of interlock between the several slots. The interlocked relation of the slots in the flange lips and in the insulating strips then assures that neither circumferential nor axial displacement of the terminals relative to the coils can possibly occur.

It is accordingly a broad object of the present invention to provide a bobbin wound relay coil having coil terminals and load line terminals which are secured to the bobbin in locked mechanical relation.

It is a further object of the invention to provide a coil, and coil and load line terminals associated with the coil, wherein the coil terminals extend in opposite directions to the load line terminals, and wherein one set of terminals is insulatedly related to the other, and arranged to provide maximum rigidity, minimum utilization of coil perimeter by terminals, and optimum separation of points of lead attachment of the coil terminals from the points of lead attachment of the terminals.

A further object of the invention resides in the provision of a relay coil wound on a bobbin, and having two sets of terminals, which are secured to the coil in interlocking relation with the bobbin by means of interlocking slots.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a view in elevation of a relay coil in accordance with one embodiment of the invention;

Figure 2 is a top view corresponding to Figure 1;

Figure 3 is a view transverse section taken on the line 3-3 of Figure 1;

Figure 4 is a view in perspective of a preferred em bodiment of the present invention;

Figure 5 is a view in section taken on the line 5-5 of Figure 4; and

Figure 6 is a circuit diagram of a typical relay system in which the relay coils and terminals of the present invention may be employed.

Referring now more particularly to Figures l-3 of the accompanying drawings, the reference numeral 10 denotes a coil of wire, consisting of multiple superposed winding layers, and having the form of a hollow cylinder. The coil 10 is wound on a bobbin 11, of insulating material, having a hollow cylindrical body 12 and two flanges 13 and 14, extending at right angles to the axis of the body 12.

A first pair of metallic coil terminals l5, 16 is provided, each having a flat strip leg portion 17 which extends generally parallel with the axis of the coil cylinder in proximity to the uppermost winding layer. The coil terminals 15, 16 are further provided each with a foot which includes a bend 13 and a connector 19, the latter extending generally parallel with the leg portion 17, although this is not essential. The bends 18 are arranged to pass over the lip 20 of one of the flanges, 13, and to abut against the lip, the connector 19 extending beyond the flange. Provided in each of the connector portions 19 is a threaded aperture 20, into which may be engaged a screw, utilized for securing wire leads to the terminals, in conventional fashion. The terminals 18, 19 are further provided with slots 21, to which may be secured and soldered the ends of the coil 10.

In accordance with a primary feature of the present invention, a pair of load line terminals 22, 23 is secured to the coil 10. The load line terminals 22, 23 may be physically identical with the coil terminals 15, i6 and are 7 not further described in detail for that reason. Each of load line terminals 22, 23 may include a flat strip portion, 24, a bend 25, a connector 26, and a threaded aperture 27 for engagement with a screw 28.

Each of load line terminals 22, 23 may be provided with a sleeve 39, of extruded vinyl material, or of other suitable insulating plastic material, which extends over the leg of the terminal only. In assembling the terminals to the coil the load line terminals 22, 23 are laid one for one over the coil terminals 15, 16, the bends of the load line terminals extending around the lip 31 of the flange 14, and the connections 26 extending therebeyond, but the threaded apertures 27 arranged generally in alignment with the lip 31. The latter feature is of value when relatively heavy load line leads are to be secured to the connectors 26, in providing a rigid support against which the screws 28 may be worked.

After the terminals have been assembled to the coil 10 electrical tape 32 is wound around the assembly, to protect the coil and to secure the terminals rigidly and immovably to the coil. The unit may be impregnated with any conventional potting compound, in accordance with usual practice.

Coil and terminal assemblies in accordance with the present invention are found to be rigid, durable and maintenance free. The superposed relation of the flat terminals results in a re-inforcement of each by the other, while the relation of the bends in the terminals to the lips of the flanges increases the axial immovability of the terminals deriving from the tape binding. Minimum peripheral space is required for the terminals, yet the load line connectors are widely separated from the coil connectors, and readily distinguishable therefrom. This results in freedom from wiring errors, and from inadvertent wrong connections or contacts between load line leads and coil leads.

Referring now more particularly to Figures 4 and 5 of the accompanying drawings, the reference numeral 40 denotes a coil of wire, consisting of multiple superposed winding layers, and having the form of a hollow cylinder. The coil 40 is wound on a bobbin 41, of insulating material, having a hollow cylindrical body 42 and two flanges 43, 44, extending at right angles to the axis of the cylinder 42. V

The flanges 43 and 44 may each have the outline of a semicircle with a rectangle superposed on its diameter, the outer edges 45 of therectangles lying in planes at right angles to the axis of the cylinder, and equidistant therefrom. Thereby, the coil may be accuratley and solidly oriented with its axis parallel to a wall or other flat surface.

Formed in each of the semi-circular lips 46, 47 of the flanges 43 and 44, respectively, is a pair of shallow slots either of which may be identified by the reference numeral 48.

A first pair of metallic coil terminals 50, 51 is provided,

each terminal having a leg portion 52, of flat strip metal,

4 cylinder 42 in proximity to the uppermost winding layer. The coil terminals 59, 51 are further each provided with a foot which includes outward bend 53 and a connector 54. The latter extends from the bend 53 generally parallel with the leg portion 52, although this is not essential.

The terminals 5%, 51 are secured as by rivets 55 extending through the legs 52, to a single strip of insulating material 56, the legs 52 lying flat against the strip 56.

Immediately under the line joining the leg 52 to the bend 53, of each terminal, a pair of slots 57 is formed in the side edges of the strip 56. The slots 57 of each pair extend toward one another, the spacing between the pairs of slots is equal to the spacing between flange lips 46, 47, the width of the slot openings is selected to be equal to the thickness of the flange lips 46, 47, and the distance between the bottoms of each pair of slots is equal to the width of slots 48. Thereby, the slots 57 of each strip 56 may interlock with an opposed pair of slots 48 in flange lips 46, 47. When so interlocked they are not susceptible of movement axially, circuinferentially or inwardly of the flanges 43, 44.

After the strips 56 are assembled to the flanges 43, 44 electrical tape 53 may be wound about the coil 40 and about the legs 52 of the terminals 59, Si, binding the latter into place and also serving as an insulator and protective covering for the coil 40. The bends '53 and the connectors 54 of the terminals extend, then, beyond the confines of the coil 40, and of the bobbin 41.

Provided in each connector 54 is a threaded aperture through which extends a screw 59, the body of which subsists between the connector 54 and the insulating strip 56, and assists in preventing damage to the latter by bending at the line joining the slots 57. The screws 59 serve for attaching wire leads to the connectors 54, and more particularly a coil energizing lead may be connected to a pair of connectors lying beyond one of the flanges, and the coil ends connected to the same terminals, as by soldering. The remaining pair of connectors may be employed for connection to a load line, and these terminals may also be connected to a pair of relay contacts, which may be closed in response to energization of the coil 40.

In the circuit diagram of Figure 6, the reference numeral 40 denotes a relay coil, energized by leads connected to coil terminals 60, which are schematically rep resented. The relay coil actuates a pair of contacts 61, which are connected to load line terminals 62, for connection to a load line 63. In the practice of my invention I prefer to utilize a relay of the mercury type, wherein energizatio-n of coil 40 serves to displace a plunger, which in turn modifies the level of a mercury pool, the mercury acting to bridge a pair of contacts. However, I do not desire to be limited to application of my novel coil and terminal arrangement in any specific or particular type of relay.

While I have described and illustrated two specific embodiments of my invention, it will be clear that variations of the general arrangement and of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope or the invention as defined in the appended claims.

What I claim is:

1. A coil and terminal construction comprising a bobbin having a cylindrical body, a first flange and a second flange, said flanges extending perpendicularly of said body, a multiple layer coil wound on said bobbin and extending to a radial distance less than that of said flanges, a pair of coil contacts having each 'a fiat leg, a bend, and a connector, said coil contacts placed in parallel relation against said coil and extending parallel to the axis of said coil, said bends extending around said first flange, said connectors extending beyond said firstv on each leg of each of said load line terminals, and cover ing said each leg, said legs of said load line terminals overlying the legs of said coil terminals and extending in opposite sense, the bends of said load line terminals extending around said second flange and the connectors of said load line terminals extending beyond said second flange, and means for simultaneously binding all said terminals against said coil.

2. The combination in accordance with claim 1 wherein each of said connectors includes a threaded aperture, and wherein at least certain of said apertures extend in substantial alignment with one of said flanges.

3. The combination in accordance with claim 1 Wherein said bends abut against the lips of said flanges internally of said flanges, to reduce the possibility of axial motion of said terminals with respect to said coil.

4. A coil and terminal arrangement comprising a first conductive terminal having a flat body and a connector end, a second conductive terminal having a flat body and a connector end, an insulating closed sleeve for insulating one of said flat bodies, said first of said flat bodies being located within said insulating sleeve, said tenninals being relatively positioned with the flat bodies thereof in proximity and in superposition and separated by an element of said insulating sleeve, and with the connector ends of said bodies extending in opposite directions, an inductive coil having a longitudinal axis, and means for securing said flat bodies against said coil and generally parallel with said longitudinal axis, said connector ends extending beyond the bounds of said coil.

5. The combination in accordance with claim 4 wherein is further provided a flanged bobbin, said coil being wound on said bobbin, said flat bodies subsisting between said flanges and said connector ends extending beyond said flanges.

6. The combination in accordance with claim 5 wherein said flat bodies are each separated from its respective end by a bend, said bends each abutting one of said flanges, said bends anchoring said terminals between said flanges.

7. A bobbin for a relay coil, said bobbin including a cylindrical body and two flanges extending perpendicularly of the axis of said cylindrical body, said flanges each including a lip, a shallow slot formed in one of said lips, a strip of insulating material, at least one terminal secured to said strip of insulating material, said strip of insulating material including two opposed slots in its edges, said slots extending toward one another in align ment, said slots having a width of opening equal to the thickness of said at least one lip, and having a separation between bottoms equal to the width of said shallow slot, whereby said strip may be interlocked with said bobbin.

8. A bobbin for a relay coil, said bobbin including parallel flanges separated along an axis and extending substantially perpendicularly thereof, said flanges each having a shallow slot in its lip, said shallow slots lying in a straight line generally parallel with said axis, a flat strip of insulatin material, a pair of terminals secured to one side of said flat strip of insulating material, said flat strip of insulating material including two pairs of slots in its edges, said pairs of slots separated along the length of said flat strip by a distance equal to the axial separation of said flanges, said two pairs of slots being arranged and adapted in interlocked relation with said shallow slots, whereby said strip may be immovably interlocked with said bobbin.

9. A bobbin for a relay coil, said bobbin including a cylindrical body and two flanges extending perpendicularly of the axis of said cylindrical body, said flanges each including a lip having a shallow slot formed therein, said slots being in axial alignment and similar, an elongated strip of insulating material, a pair of terminals secured to said strip of insulating material and extending in opposite directions, said elongated strip of insulating 6 material having two pairs of opposed slots on the edges thereof, the slots of each pair'extending' toward one another and in alignment, said slots having each a width equal to the thickness of said lips and having a separation between bottoms equal to the width of said shallow slots, whereby said strip may be interlocked with said bobbins.

10. A relay coil and terminal arrangement comprising a relay coil, an insulating bobbin on which said coil is Wound, said bobbin having a generally cylindrical body and two flanges extending perpendicularly of the axis of said cylindrical body beyond the circumferential confines of said coil, a first pair of terminals extending in opposite directions in substantially the same plane and in relatively insulated relation, a second pair of terminals extending in opposite directions in substantially the same plane and in relatively insulated relation, means securing said pairs of terminals firmly against said coil, said pairs of terminals extending parallel to the axis of said cylindrical body at different angular positions about the circumference of said coil, the separate terminals of each of said pairs of terminals extending outwardly of said flanges in the direction of the axis of said cylindrical body and including means for interlocking said terminals with said flanges and against motion with respect to said flanges in the direction of said axis of said cylindrical body.

11. A relay coil and terminal arrangement comprising a relay coil, an insulating bobbin on which said coil is wound, said bobbin having a generally cylindrical body and two flanges extending perpendicularly of the axis of said cylindrical body beyond the circumferential confines of said coil, a pair of terminals extending in opposite directions in substantially the same plane and in relatively insulated relation, means securing said terminals firmly against said coil, said terminals extending parallel to the axis of said cylindrical body, the separate terminals of said pair of terminals extending outwardly of said flanges in the direction of the axis of said cylindrical body and including means for interlocking said terminals with said flanges and against motion with respect to said flanges in the direction of said axis of said cylindrical body.

12. In combination, a bobbin having a longitudinal axis, a pair of longitudinally extensive terminals, an insulated mounting strip for said pair of terminals, said terminals being secured to said insulated mounting strip and extending in opposite directions, generally parallel to said axis, said bobbin including a body and parallel flanges extending perpendicularly of said body, said flanges and said mounting strip having complementary slots in edges thereof, and means including said complementary slots in edges of said flanges and in edges of said mounting strip for securing said mounting strip to said ranges in interlocked relation, said slots being all three sided slots, said slots in said mounting strip having a dimention in the direction of said axis substantially equal to the thickness of said flanges at the point of interlock therewith, and said slots in said flanges having each a width substantially equal to the distance between the bottoms of adjacent slots of said mounting strip.

13. In combination, a bobbin, a pair of longitudinally extensive terminals, an insulated mounting strip, said terminals being secured to said insulated mounting strip and extending in opposite directions, said bobbin including parallel flanges, and means including complementary slots and extending in opposite directions in edges of said flanges and in edges of said mounting strip securing said mounting strip to said flanges in interlocked relation, wherein said mounting strip and said terminals are substantially coextensive and wherein said terminals include connectors extending beyond said flanges axially of said bobbin in opposite directions, and wherein said terminals include legs falling at least largely within the confines of said flanges, whereby said terminals and said mounting strip may be bound to said bobbin by means of tape wound circumferentially of said bobbin between said flanges.

References Cited in the file of this patent UNITED STATES PATENTS 1,795,411 Sprague Mar. 10, 1931 2,184,272 Driftmeyer Dec. 26, 1939 2,249,057 Stahl July 15, 1941 Dunleavey et a1. Aug. 15, 1944 Price Nov. 16, 1 948 K9011; Oct. 25, 1949 McKinney Nov. 28, 1950 Thulin Aug. 26, 1952 Meeks Mar. 31, 1953 Long Aug. 4, 1953 

